Best Broker For Automated Trading

So I'm about to take my trading from manually trading my signals to fully automated execution.

I currently trade with FXCM UK and have been happy with them, but the only APIs you can use are for strategies coded in C++, and I happen to be in C#.

They've offered to have their programmers re-code it, but at considerable cost to me. My progammer can do it as well, but will take him a much longer period of time. It all comes down to cost, time and trust issues that have lead me to just finding a different broker as the best option for automated.

The question is, which to go with? I don't want to deal with dealing desk models, and would prefer somewhere that has good liquidity and will allow me to get bids hit and offers lifted. Is there any such place?

I have a decent sized account, but not nearly enough to be considered at a major shop.

So I'm basically looking for an alternative to retail, maybe something that could be categorized as in between retail and institutional.